Determination of Linezolid in Human Plasma by High-Performance Liquid Chromatography With Ultraviolet Detection

• DOI: 10.1097/ftd.0b013e3181d5eeee
• Publication Date: 2010-03-18T09:34:48Z
• Authors: Dario Cattaneo; Sara Baldelli; Francesca Conti; Valeria Cozzi; Emilio Clementi
• Keywords: Linezolid; Reproducibility of Results; Blood Proteins; 3. Good health; 03 medical and health sciences; 0302 clinical medicine; Anti-Infective Agents; HPLC; human plasma; linezolid; pharmacokinetics; therapeutic drug monitoring; Acetamides; Calibration; Humans; Indicators and Reagents; Spectrophotometry, Ultraviolet; Drug Monitoring; Biotransformation; Chromatography, High Pressure Liquid; Oxazolidinones

A high-performance liquid chromatographic method for the determination of linezolid in human plasma was developed and validated. After precipitation of plasma proteins with perchloric acid, the protein-free supernatant was separated by isocratic reverse-phase chromatography on a X Bridge C18 column. The mobile phase consisted of a mixture of phosphoric acid 0.05%: acetonitrile (75:25, v/v) with a flow rate of 1 mL/min. The column elute was monitored at 254 nm. The method was linear from 0.2 to 48 mg/L (mean r2 = 0.9996, n = 10). The observed intra- and inter-day assay imprecision ranged from 2.83% to 8.16% (18.80% at the lower limit of quantification); inaccuracy varied between -0.33% and 8.18%. Mean drug recovery was 99.8% for linezolid and 90.0% for the internal standard (para-toluic acid). The method was found to be precise and accurate and suitable for therapeutic drug monitoring of linezolid in routine clinical practice.